The potential of theft or damage to personal computers has caused consumers to resort to a wide variety of security methods. Heretofore, the available security solutions for personal computer users were general purpose in nature and largely based on designs that were developed for the general office equipment marketplace. Because office equipment including personal computers seemingly varied in size, shape, and construction, inventing a common security solution for these items have proved elusive. As an example, typewriters vary so dramatically that it is impossible to come up with a common method either to bolt them to a table or to attach a steel cable to them. Consequently, a user must determine, based on his or her particular equipment, what device is the best. Generally, the selection involved compromises. Prior art discloses many efforts to provide broadly applicable security devices, none of which provide a common, inexpensive and secure method to protect personal computers. One particular class of devices utilize adhesive with interlocking plates to glue the bottom of the office equipment to the work surface. U.S. Pat. No. 4,655,429 to Gaenzle et al. (1987) discloses a fixture that uses plates and a bonding method to secure them. Other methods have the user drill holes in the desk to bolt the interlocking plates together from underneath the table. These methods are satisfactory for certain high risk applications but generally are unacceptable because they make movement of the equipment time consuming and difficult when offices are relocated; sometimes force permanent modifications to be made to the equipment or anchoring location; and do not allow the user the latitude to even slightly reposition the equipment once it has been installed. In addition, any of these devices must be manufactured to fit the specific geometry of the machines they secure, making them expensive to manufacture and buy.
Another class of devices that share many of the same drawbacks encase the equipment to be protected in a protective housing using various methods to anchor the housing to a secure location. Several types of these devices have been disclosed--for example U.S. Pat. No. 4,123,922 to Kuenstler (1978) describes various means to lock equipment inside a protective housing. U.S. Pat. No. 4,252,007 to Kerley (1981) discloses a protective housing of similar intent but different design. Although appropriate for high risk applications, these devices must be designed to house a particular size of equipment making them expensive to manufacture and sell. They have the added drawback of dramatically altering the way the office equipment looks and in some instances feels; making them unattractive; and creating a less than positive environment for the office staff that operates the equipment. My own U.S. Pat. No. 4,843,848 (1989), although less encasing than those described above, also suffers from the problem of being geometrically specific to the equipment it is protecting.
To overcome these objections, consumers have resorted to security devices that have more flexible anchoring methods. Many of these devices utilize steel cable, sometimes referred to as wire rope, to tether personal computers in place. Some steel cable devices can use adhesive as the method to attach the cable to the office equipment. Generally, this involves a plate that is bonded to the equipment with adhesive. The cable is then attached to the plate. U.S. Pat. No. 4,733,840 to D'Amore (1988) discloses one such device that uses a bendable member as part of the plate. This method of anchoring is somewhat advantageous because it is usable across a wide variety of office equipment and is easily installed. Furthermore, the cost of manufacture is low. The disadvantages to the adhesive plate approach are sometimes quite severe. To provide a strong bond, adhesive requires a smooth, flat and clean surface. The majority of personal computer surfaces are rough and covered with slick coatings (polyurethane enamels or silicone). Consequently, the degree of security provided by adhesive plates is always questionable and unpredictable.
Another steel cable device uses existing screws to secure the cable to the office equipment. First, a bracket is mounted to the equipment using an existing screw. Then the steel cable is passed through the bracket, blocking removal of the screw. These devices can be used on a broad variety of computers; are inexpensive to manufacture; and can be removed when no longer desired. They, however, have disadvantages. First, the security provided by this method is based on the strength of the screw arrangement which anchors the bracket. Most personal computers have relatively small, frail screws. Additionally, the surfaces that they screw in to are generally of the thin, sheet metal variety. Consequently, a thief, depending on the personal computer, could dislodge the bracket with a good quick tug. Another disadvantage is the difficulty that users encounter mounting these devices. Many users have a difficult time visualizing how these devices are utilized and installed.
Another steel cable device uses a tether to anchor a housing that encases the equipment. This approach has the same drawbacks as the other protective housing approach that was mentioned above. They dramatically alter the look and feel of the equipment they are protecting and create a negative image in the workplace.
Still other office equipment steel cable devices as disclosed in U.S. Pat. Nos. 3,785,183 to Sander (1974); 3,859,826 to Singer et al. (1975); 3,990,276 to Shontz (1976); and 4,300,371 to Herwick et al. (1981) all focus on elaborate keylock assemblies but do not focus on, or provide any insight into a simple and common method to attach the steel cable to a personal computer or other office equipment. For attaching the cable to equipment to be secured, Sander suggests making a hole in the equipment to take advantage of the disclosed lock and back plate assemblies. Most users find this unacceptable because they do not wish to drill a hole for fear of violating the warranty or damaging the equipment. Singer et al. suggests using tamperproof screws to attach to the equipment to take advantage of the disclosed locking assembly. This assumes that there are suitable screw mounting locations that are in the necessary location to mate with the particular security plate for the equipment. Additionally, security screws are only suitable as long as a thief does not have the correct screwdriver. Shontz suggests drilling a hole in the office equipment; or finding a suitably located and sized hole; or adapting a plate to fit existing nuts and bolts to mount the cable as to take advantage of the disclosed locking assembly. This approach has many of the same disadvantages that are found in the Sander disclosure.